An Amtrak train headed from Vermont to Washington, D.C., on Monday hit rocks that had fallen onto the track from a ledge, spilling the locomotive and a passenger car down an embankment, derailing three other cars and injuring seven people, authorities said.
The Vermonter train, carrying 98 passengers and four crew members, derailed at around 10:30 a.m. in Northfield, 20 miles southwest of Montpelier, they said.
"This was a freak of nature," Gov. Peter Shumlin said.
One of the injured people was airlifted to a New Hampshire hospital and was being evaluated in its emergency room. The six others went to a local hospital with injuries including neck, back and shoulder pains and lightheadedness.
The Federal Railroad Administration said a crew member was seriously injured. Four hospitalized people were released by Monday evening, Amtrak said.
Passenger Bob Redmond, of Bay City, Michigan, was taking a foliage tour and sitting in the front row of the third car when the train derailed. He looked outside the window and saw the car that had been ahead of his was now alongside him.
"It was just going the other way, and we started tipping sideways and down we went," he said.
The National Transportation Safety Board was investigating, board spokesman Eric Weiss said. It was sending a small team rather than the full-blown effort made for a fatal Amtrak derailment in Philadelphia in May.
The track where Monday's crash occurred had been part of a $220 million upgrade of New England Central Railroad tracks funded with help from a $50 million federal recovery grant. In early 2013, after the upgrade had been completed, the speed limit in the area was increased from 55 mph to 59 mph.
Shumlin said there was no reason to believe there was any negligence on anyone's part.
"We don't have all the details, but this track was rebuilt, it was state-of-the-art track," he said. "Ledge slides happen."
Federal records show the company that operates that stretch of tracks, which is part of the Genesee and Wyoming Railroad, has had four accidents since 2006 that could have involved debris on the tracks. In the railroad's 54 accidents since 2006, three people died.
Federal safety rules for tracks that carry passengers require at least two inspections every week, with at least one day between inspections.
State officials said a freight train had passed over the tracks Sunday night with no problems.
When asked if there was technology available that could have detected the slide before the train went through, officials said no.
"There is not really anything that's going to detect this kind of thing," said Dan Delabruere, the rail chief of the Vermont Agency of Transportation, who spoke at a news conference with Shumlin.
Numerous derailments around the world have been caused by debris on tracks, many linked to heavy rains that trigger slides or heavy winds that knock down trees. In 2010, a train in Beijing hit mounds of debris left on the track following a landslide, killing 19 people.
The region near Monday's derailment received 2.5 inches of rain between Thursday and Friday, the National Weather Service said.
Rail company officials confirmed details of the crash but did not immediately provide a comment.
The Vermonter takes the route daily, beginning in northern Vermont. The 13-hour, 45-minute trip leaves St. Albans, Vermont, at 8:58 a.m. then passes through Springfield, Massachusetts, and New York, with D.C. as the destination.
Three cars that left the track Monday remained upright.
Tracy Zaplitny, also of Bay City, said she and other passengers broke a window to get out of the train.
"It's a huge wreck up there," she said.
At least several dozen passengers were loaded onto school buses to be taken to an armory at nearby Norwich University. Passengers helped each other after the crash.
The clearing of the track was to begin immediately, although officials did not know how long it would take before the section is reopened. Amtrak planned to bus passengers booked on the Vermonter to and from Springfield.
Associated Press writer Joan Lowy contributed to this report from Washington, D.C.